The use of automated devices is widespread nowadays, and finds countless applications. For instance, robots perform very precise and delicate tasks in the construction of electronic devices, or in medicine and aviation. Robots are also used in applications which require motion, notably, for automatic warehouses, where goods are retrieved and stored by means of computed-actuated robots. Other applications include, e.g., fetching raw materials in the course of industrial manufacturing, and removing and packaging finished pieces. In home, or domestic robotics, attempts have also been made to exploit robots for such tasks as lawn mowing, snow-blowing, leaf-clearing, floor cleaning, pool cleaning and vacuum cleaning. Hereinafter, the terms domestic robotics and home robotics are used in contradistinction to industrial robotics; thus, the user of a home or domestic robotic system will be an average consumer and cannot be presumed to have the skills required to carry out complex maintenance or setup of the system, as might be the case in industrial robotics. In addition, ease of use and simple and robust setup procedures may be particularly important in home or domestic robotic systems. It will therefore be noted that a sub-category of such domestic robots is garden-based robots, which include robots able to perform the aforementioned tasks of lawn mowing, snow-blowing and leaf-clearing. Robotic lawnmowers are a particularly commercially successful example of such an autonomous machine, substantially reducing the time and effort required on the user's part in order to maintain a neatly-kept lawn.
By their very nature, autonomous machines such as robots represent a significant labour-saving for consumers. Repetitive and time-consuming tasks may now be carried out without significant supervision or instruction by the user of such autonomous machines. In order to further reduce the amount of supervision and instruction necessary, sophisticated control systems have been proposed that further increase the independence of the machines. Area coverage by robotic appliances is used in a growing number of applications, such as robotic lawn mowers, robotic vacuum cleaners, robotic window cleaners, robotic painting and the like. In such applications the robot is typically moving within a working area (such as the floor of a room, in the case of a robotic vacuum cleaner, or a lawn or garden in the case of a robotic lawnmower or snowblower) defined by a boundary. The robot may be provided with sensors (such as tactile, optical, electromagnetic sensors etc.) to detect this boundary directly.
The robot typically carries a payload (which may include one or more cutting blades, vacuuming nozzles, rotating brushes, painting brushes etc., depending on the function that the payload is intended to provide) across the entire area until adequately covered. There are various strategies of area coverage, such as random and systematic coverage and various paths of movement used for the actual scanning such as straight lines (either parallel or with varying directions), spirals etc.
Even with the numerous control systems and methods for autonomous navigation by robots within a working area, navigation of a domestic robot within a working area has not yet been perfected; for example, issues in terms of efficient coverage of the area, ease of setup of the system and safety remain. Aspects of the invention may address one or more of these issues and may additionally or instead address other issues in domestic robotics.